Scientists Say Friends Share More DNA

Scientists from Yale University say their research indicates that people who are friends share more DNA than those who are strangers. The scientists also suggest that, in terms of evolution, genes that evolve similarly among friends (as opposed to among non-friends) better afford natural advantages. That is, their benefits may be supplemented through cooperation among the friends during activities that require the genes to be in use. In this, the genes tend to naturally select the group of friends over isolated carriers of the genes. Per the article:

People may unsuspectingly choose friends who have some DNA sequences in common with them, a new analysis finds. Researchers compared gene variations between nearly 2,000 people who were not biologically related, and found that friends had more gene variations in common than strangers...."Imagine you're the first person on the planet to evolve the capacity to speak," Christakis told Live Science. "Do you think that mutation would increase your Darwinian evolution? No. Because you would have no one to speak to." The usefulness of a speech gene would depend on whether a friend shared the same gene, Christakis said. In other words, there's an advantage to people's genes evolving in relation to those of their friends....The study was published today (July 14) in the journal Proceedings of the National Academy of Sciences.

The scientists are probably speaking in general terms rather than absolute ones. That is, I don't think they are saying that in every case friends share an abnormally high amount of DNA. I think the scientists are saying that, generally speaking, friends share more DNA than non-friends and that this suggests that our DNA might have something to do with the friends we choose.

Are people actually choosing friends based on their DNA or is it simply choosing friends with certain physical characteristics which have been determined by their DNA? For example, I read somewhere that people preferentially choose partners who look similar to themselves. It seems to me that we could choose a friend because of a particular characteristic, like the way they look, but their DNA could be quite different to ours in other ways. Not my field so happy to hear other people's thoughts (and be corrected ;-)

The scientists tried to adjust for the possibility of choosing friends according to looks. Per the article:

The researchers acknowledged some caveats to their conclusions. For example, it may be that people form friendships with those of the same ethnicities, they said. But to take this into account, the researchers studied participants from a homogenous group of people, from a Caucasian background.

It might be that people tend to make friends with others who have the same interests or that extraverted people tend to make friends with each other. This would be logical if interests and extraversion were founded to some degree in DNA. I don't know much about it either.

Would it just be that those who share more things on a genetic level, probably just have similar traits, and are more likely to be friends or at least friendly...?

This strikes me as a big 'duh' moment. I suppose that it's kind of kewl to see a correlation, but I think that it is pretty much a given, we tend to share more traits with those who are near us, and the more things we have in common, the more likely it is that we will be friendly. I guess you can have a chicken/egg type discussion about it. Just like those who think more with their lizard brain (fear) tend to watch faux...

...and for the record, it was 'egg', there were eggs long before there were chickens. It's a simple answer. XD

I agree that it seems logical that having more common DNA would on average make people more predisposed to becoming friends.

As most people know Carl Jung was a psychiatrists who said there were different personality types. His ideas were followed up on by other psychiatrists and psychologists and finally led to the Myers-Briggs Type Indicator (MBTI). The MBTI is a test that is supposed to determine what personality type a person is among 16 possibilities. According to the MBTI the16 basically different types may be identified in terms of four dichotomies. For example, I am an INTJ type. That means I am Introverted as oppose to Extraverted, use iNtuition when gathering information as opposed to only my five Senses, make decisions by Thinking logically as opposed to any subjective Feelings that I might have and tend to make Judgements as I relate to the outside world instead of tending only to classify Perceptions as I relate to it. The opposite of my type, of course, is ESFP. Clarifying further, some other types are INFJ, ESTP, ISFP, etc. Again, there are 16 different types.

My understanding is that evidence suggests that although people can develop in every category (I, E, N, S, T, F, J, P) they are born to their basic personality types. If this is true then a person’s basic type would be coded in his or her DNA. Assuming that it is and people of the same or similar types are more likely to become friends then it is logical that, all other things equal, friends on average would share more DNA at least of the type that determines personalities than strangers.